It is known to repair degraded steam generator tubes by process called electrosleeving, which involves electrochemically depositing an ultra-fine grained nickel on the inner surface of the degraded steam generator tubes.
An example of electrosleeving is disclosed in U.S. Pat. No. 5,352,266, which describes a process for producing nanocrystalline nickel having a grain size of less than 11 nanometers. U.S. Pat. No. 5,352,266 is hereby incorporated by reference herein.
U.S. Publication No. 2010/0269960 discloses a method of processing a component of zirconium or hafnium alloy by nano structuring a surface layer of the component so as to confer on the alloy over a thickness of at least 5 micrometers (μm) a grain size which is less than or equal to 100 nanometers (nm).